Foamie Yf-23 Black Widdow II

hey guys, i found plans for this on some foamie web site, and sense its on my top 3 list of favorite jsets, i couldnt resist. im doing it EDF stlye, but it can be easily done pusher as well. its very close to a true scale outline, and the only big change i made was to the size of the tailerons, they were too small on the plans. also, no cg was noted, so i found it by making a few chucks. it only took about 1 sheet of depron, and about 2.5 hrs to build. i still need to add control surfaces, and i really want to do full flying stabs, because this is a "test bed" for a larger, twin EDF version some where in the future...so this is kinda the test rat. fan is a e-flite fan, motor will be a e-flite 4200kv inrunner...est weight RTf is about 14-15oz with a 2100 3s pack, and about 230-240 watts. should have 1-1 thrust ratio, if not a hair more. stay tuned! i want to put gear on it too...ny maybe a quick paint job.

Foamie Yf-23 Black Widdow II

CG is pretty far forward. at about 18-20% of the chord. yeah, the 150% full body version wil have 2 fans. maybe 140%. i dont want it to get real big becasue of perf issues on these fans. 150% would put me at 33" wingspan, and 54" long...so maybe 130-140% would be best. 54" long is pretty big for 2 of these fans....it would fly, but not how i would want it too...we need speed capitan! the 3D verison should be alot of fun though.

Success!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!

hey guys, well, i must say, i was pretty nervous about this maiden, being as alot of guys havnt had too much success with a EDF YF-23....YET. i got the cg from chucking it, so i figured that would have to work. got it done today, went out to the field and i couldnt believe i was strappin a brand new thunder power prolite 2100 3s hanging out there on the tip of that depron...i knew if she went in, the batt would be toast, and i didnt want that. ..anyways, the wind was blowing at about 10-15 mph and it was pretty turbulant, as you'll see in the vids. regardless, i couldnt go home now, besides, a "breeze" always helps with a first hand launch. it handled the wind even being a pretty small model. the first flight was pretty good, and didnt take much trim, but when ever i got it slow, it would pitch straight up! i saved it about 3 times on one landing...what was weird was that it flew great with a little speed...so im thinking the CG is a little too far aft, as the pitch was rather sensitive as well. so i landed strapped on 3 dimes up front, and most of the pitch issue was now gone. its alot of fun to fly, and looks totally wicked in the air, just like the real black widow was. now that i know it flys well, and its fairly stable...im going to build a twin EDF version, full fuse with 2 of the same fans like what im using now. the weight now is about 15-16 oz and its got some sweet vertical. one thing we noticed, was that the weight of the fan up top was making it fly a little funny in the wind, as it would osilate(sp?) a little...but it was also pretty gusty. now i need to put some gear on it, and paint it and have fun with it until the larger, 54" long, 33" wingspan twin with retacts in done...dont hold your breath, that one could be a few months off yet. for now, i'll continue to test out stuff on the litte guy so i dont pile in the soon to be larger version. also...the ruddervators are a big no no...a little didnt do much, but if you used alot of rudder, it did some crazy stuff... check out the vids, and keep in mind thisis a 15 oz model, 22" wing span flying in 10-15 mph winds...i cant wait to fly when its calm to prove she is a smooth flying ace. and just like my dad says in the vid...its another one they should have bought...anyways, heres the vids, and some pics.
Brent
ps...no evident tip stalls..
vid
NOTE...i was going to have a friend bring a RADAR gun to check the speed...but then i thought...what good would that do? 0 mph isnt possible! northrop...the LO masters!

Hmmm.. The *pitch up* Might come from that High Thrust Line too...
If it flies fine @ higher RPMS/Speed and then you try to slow it all down you minimize that Jetwash over the tail, hence *possibly* the pitch up tendency.
Just my .02
Good job!
Vic.

I flew it for a lap or two ...it felt good ...although it is hard to see the tail,they blend into the fuse and you cant see them.this is exactly like the real ones where when they flew ....it was such a cool plane and very different than any thing else flying. some times it kinda looked like a SR-71 when it was on final.any way i think the real one had it's elev pivot pretty close to what the "NUT" has . but i think the thrust line could be the real demon here but a lot can be llearned from this little guy...or shou;d i say "little PAV." way to nut ...know focus on the A-4 man ...one plane at a time....shesssh

Outstanding...have been looking for YF-23 plans for a while now. Its hard to even find a decent 3-view. Forget about finding a plastic model to get a 3-d view...Even E-bay doesnt even have them. Where did you find plan, would love to do a full fuse version for pusher prop. Again, outstanding job!!!!!!

Congrats Brent! Another fine Northrop machine....glad to hear you got her flying successfully and started ironing out the design challenges! Looking forward to seeing you tackle twin EDF's and a 3D fuse...now get back on that A-4 like your dad says!

dont worry paul, the A-4 will be in the air this weekend, then comes the paint i couldnt resist when i saw the plans for this...once again i have heavily moddified somebody elses design...i think its some kind of desease ????

So you're using conventional ailerons with the ruddervators mixed to give pitch control?

I'll bet the odd rudder behavior comes from then creating a *huge* amount of adverse roll. With surfaces that large, suck a low V angle, and a fairly short tail moment adverse roll has got to be a big issue.

(Always wanted one of these, BTW. I figure I'll start with a pusher profile similar to yours but built in Shockflier style, but haven't gotten around to it yet.)

the link above is where i got the plans from, but i enlarged the elevators becasue they were too small, the rest of the model is pretty close to scale, i also made changes to the lower center fuse, engine nacels, and from the inlet back to a more scale shape. the ailerons and ruddervators are not mixed. rather it has conventional ailerons, and sense its V tail, the elevators are also used as rudders, though with quite scary results... they do work great when doing high alfa though...but anything faster than that it does some violent stuff. its alot of fun, just know that the plans on that link kinda suck because they were scanned in, and the pages dont match well, requiring you to "fill in the blank" if you guys build them, i'll let you know where i have my CG as there is none noted on the plans.